1. Field of the Invention
This invention relates to an unsaturated polyester especially an unsaturated polyester which, when formed into a final object has improved physical properties, especially an improved Martens thermal stability of shape. This invention is also directed to a process for the preparation of such unsaturated polyester, solutions of the unsaturated polyester in copolymerizable monomers and formed objects thereof, especially sheets of improved thermal stability of shape.